€. T. Clough — Dkappearmice of Limestones, High Teesdale. 259 



I append a revised estimate of the total thickness of the Purbeck 

 Beds in the Vale of Wardour, if the Upper group is to be restricted 

 within the limits indicated by Mr. Woodward. 



ft. in. 

 Mean thickness from top of No. 30 to base of limestone \ -ry* 



with f7mo (part of 21) 12 ( p^P^®^, 



Yellow sands with ^w^ertiiles 6 (il^T^f' 



Grey clays and marl 4 o) ^^ ^^et. 



Thickness from top of JSTo. 19 to top of the ArchceoniscMS 



bed (No. 13) 7 



From top of No. 19 to top of cinder bed (south of 



Teffont) 4 3 



From top of cinder bed to base of the ' scale ' below 



the flagstone at Teffont 11 0. 



From base of ' scale ' to marl-band below the 5th Lias 15 9 ^ 

 Section in Ridge quarry from marl below ' Lias ' to Lower 



bottom of quarry 19 10 J- Purbeck, 



Allowance for gap between quarries 7 oj 64| feet. 



Section at Wockley from surface to base of Purbeck Beds 22 0-^ 



Total 108 10 



Middle 

 Purbeck, 

 221 feet. 



IV. — The Disappearance op Limestones in High Teesdale.^ 

 By C. T. Clough, M.A., F.G-.S., of H.M. Geol. Survey, 



IN High Teesdale, on certain hillsides, the structure of which is in 

 most respects clear, the observer is struck by the disappearance 

 of some, generally constant, limestone which ought naturally to 

 occur. The limestone most usually missing is the Great Limestone, 

 which, with the exception of the Melmerby Scar Limestone, is the 

 thickest of all in the dale. Though the ground is almost free from 

 peat and drift, and plainly shows the banks formed by the Four 

 Fathom Limestone and Firestone,- there is yet perhaps neither bank 

 nor ' shake-hole ' (swallow-hole) to i-epresent the Great Limestone. 

 In the cases referred to the difficulty cannot be accounted for by 

 supposing that the limestone along its outcrop is thrown out by 

 a fault, for the outcrops of the beds above and below can be followed 

 round the hill without interruption. 



Where the limestone disappears many masses of sandstone are 

 usuallj'' found, most of which seem somewhat disturbed ; and, in 

 the small streams, thin irregular bands of soft, rather siliceous, clay 

 and iron ochre occur. The clay and ochre represent the limestone, 

 which, in the language of the dalesmen, has been ' eaten away ' 

 along the outcrop and replaced by ' famp.' 



1 The substance of this communication was written 25 years ago. Since then 

 Mr. F. Rutley has written " On the Dwindling and Disappearance of Limestones" 

 (Q.J.G.S., 1893, vol. xlix, p. 372), but he makes no mention of their special 

 liability to dwindle in the neighbourhood of faults and veins, and gives no instances 

 of their disappearance on a large scale. Mr. J. R. Dakyns has written a short paper 

 " On ' Flots ' " (Report Brit. Assoc, 1881, p. 634), and the material in many ' flots ' 

 seems of much the same nature as ' famp.' The writer has recently seen an instance 

 of famping, differing somewhat from the examples in Teesdale, in one of the lime- 

 stones (the Skateraw Middle Limestone), which has been quarried at Catcraig, near 

 Dunbar, and this has recalled the subject to him. 



- The Four Fathom Limestone is a little below the Great, and the Firestone is 

 a sandstone a little above the Great Limestone. 



